Even as a potential leper was isolated seven days, so one who had leprosy, but then experienced healing, had to go through a seven day period also for the pronouncement of cleanliness,

“And he shall sprinkle it seven times on him who is to be cleansed from the leprosy, and shall pronounce him clean, and shall let the living bird loose in the open field. He who is to be cleansed shall wash his clothes, shave off all his hair, and wash himself in water, that he may be clean. After that he shall come into the camp, and shall stay outside his tent seven days. But on the seventh day he shall shave all the hair off his head and his beard and his eyebrows—all his hair he shall shave off. He shall wash his clothes and wash his body in water, and he shall be clean” (Leviticus 14.7–9).

We have seen how seven completed other things, so we see it here also. Seven days of isolation and seven days to pronounce one clean of leprosy showed a completion of the job.